With a protective slag in a casting mold, a high pull rate on a continuous casting site is achieved, the quality of cast billet can be improved and the number of times of steel leakages can be reduced. In a continuous casting, it is extremely important for improving the quality of cast billet that, the thickness of the protective slag in the casting mold is strictly controlled and the protective slag is added uniformly on a molten steel surface.
At present, generally, the thickness of a protective slag in a slab casting mold on a converter steelmaking continuous casting site is measured in a manual measurement manner, and then a slag-adding is predicted based on the manually-measured thickness. However, the manual measurement has disadvantages such as a large manual workload, a large measuring error and measuring not in real-time and on-line, thus it can not direct a slag-adding efficiently and reliably.